The present invention relates generally to vehicle wheel balancer and brake lathe systems, and in particular, to components configured to facilitate the centered mounting of vehicle wheels having a variety of hub pilot hole sizes and lug hole configurations on a vehicle wheel balancer spindle, as well as the centered mounting of a vehicle brake drum or brake rotor onto a brake lathe machine.
A variety of components are utilized to facilitate the centered mounting of vehicle wheels on a vehicle wheel balancer system, and the centered mounting of vehicle brake drums or brake rotors on brake lathes. Centering cones fitted over the spindle shaft of the wheel balancer or brake lathe system provide a center support sized to receive a corresponding hub pilot hole of the wheel, brake rotor, or brake drum. Due to the lack of standardization of hub pilot hole diameters on automobiles, there is a large range of hub pilot hole diameters which centering cones must encompass. A centering cone is configured with an axial bore of uniform diameter, sized to fit over the spindle shaft of the wheel balancer or brake lathe system. To accommodate as many wheels, brake rotors, or brake drums as possible, the outer surface of each cone is tapered to provide a frustoconical surface to receive the inner surface of a hub pilot hole.
It is known to those of ordinary skill in the balancer field that a lower included angle on a centering cone will provide for better centering of an associated wheel, brake rotor, or brake drum. However, to encompass the entire required range of hub pilot hole diameters which are commonly seen in the vehicle service industry with low-included angle centering cones, a greater number of centering cones is required. In order to ensure complete coverage of a range of pilot hole diameters, it is further desirable to provide for some degree of “overlap” in each centering cone. The “overlap”can be defined as the portion of each subsequent centering cone in a set which has the same range of diameters. Alternatively, this can be described as the situation where the major diameter of a centering cone is slightly larger than the minor diameter of the next larger centering cone in the set.
The total number of centering cones required to cover a specific range of hub pilot hole diameters is defined by the angle chosen for the conical taper, the length of the taper, and the amount of overlap desired between each centering cone in the set. Typical centering cones used with automotive service equipment have a single taper on each piece, and a minimum amount of overlap. From here on “taper” will be defined as having all the dimensions necessary to define a frustoconical portion of a cone: maximum diameter, minimum diameter, and the included angle.
Traditionally centering cones have been approximately 1.5″ to 2.0″ tall. This has been done to minimize the number of cones required to cover a desired range of pilot diameters. Current design trends in automotive wheels are producing many wheels with diameters inside the center bore that are smaller than the pilot diameter. For proper centering it is necessary for the centering cone to contact the wheel on the proper pilot diameter only. Not one of the alternate diameters inside the center bore. This is making it necessary to design centering cones that are shorter than in the past. Many cone manufacturers are releasing many short cones to cover these applications.
One system for minimizing the number of centering cones required in a set is to utilize centering cones having two opposing tapers on the same unit. These centering cones are of unitary construction, having their maximum diameters centrally disposed, such that the cone is merely reversed on the spindle to switch from one taper to the other. In order to ensure complete coverage for the entire range of pilot hole diameters likely to be encountered during vehicle service, a significant amount of overlap is provided between tapers. However, it has been found that when cones are provide with relatively small included angles, i.e., low taper angles, and small differences in diameters, it becomes difficult for an operator to distinguish one cone from another. The typical method for selecting a suitable cone for use is to look at the pilot hole diameter of the wheel, brake rotor, or brake drum, and make an educated guess as to which cone is most suitable, A trial and error process then ensues until a suitable centering cone is found. Accordingly, it would be highly desirable to provide a method for selecting and identifying suitable centering cones for use in mounting a vehicle wheel, brake rotor, or brake drum on a rotating spindle of a balancer or lathe which does not require extensive trial and error.